U.S. patent application number 10/369429 was filed with the patent office on 2004-06-17 for magnetic resonance imaging capable catheter assembly.
Invention is credited to Gray, Robert W., Helfer, Jeffrey L., Weiner, Michael L..
Application Number | 20040116800 10/369429 |
Document ID | / |
Family ID | 27757679 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040116800 |
Kind Code |
A1 |
Helfer, Jeffrey L. ; et
al. |
June 17, 2004 |
Magnetic resonance imaging capable catheter assembly
Abstract
A catheter assembly which is provided with a distally positioned
magnetic resonance imaging coil, comprising a cable assembly having
a proximal end and a distal end, the cable assembly further
comprising an outer tube, a first electronics assembly disposed
within the distal end of the cable assembly, a first fiber optic
strand disposed within the tube, and connected to the first
electronic assembly; and a tip assembly connected to the distal end
of the cable assembly further comprising a thin structural wall
forming a cavity, and a coil assembly disposed within the cavity.
The catheter assembly enables high resolution magnetic resonance
imaging of tissue proximate to the assembly, as well as other
beneficial diagnostic and therapeutic procedures.
Inventors: |
Helfer, Jeffrey L.;
(Webster, NY) ; Gray, Robert W.; (Rochester,
NY) ; Weiner, Michael L.; (Webster, NY) |
Correspondence
Address: |
HOWARD J. GREENWALD P.C.
349 W. COMMERCIAL STREET SUITE 2490
EAST ROCHESTER
NY
14445-2408
US
|
Family ID: |
27757679 |
Appl. No.: |
10/369429 |
Filed: |
February 19, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60357935 |
Feb 19, 2002 |
|
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Current U.S.
Class: |
600/411 |
Current CPC
Class: |
G01R 33/285
20130101 |
Class at
Publication: |
600/411 |
International
Class: |
A61B 005/05 |
Claims
I claim:
1. A catheter assembly comprising (a) a cable assembly having a
proximal end and a distal end, said cable assembly further
comprising an outer tube, a first electronics assembly disposed
within said distal end of said cable assembly, and a first fiber
optic strand disposed within said outer tube and connected to said
first electronic assembly, and (b) a tip assembly connected to said
distal end of said cable assembly further comprising a thin
structural wall and a cavity formed within said thin structural
wall; and a coil assembly disposed within said cavity, wherein said
coil assembly is connected to said first electronics assembly.
2. The catheter assembly as recited in claim 1, further comprising
a first tube and a second tube disposed within said outer tube of
said cable assembly and passing into a sealed chamber disposed
within said distal end of said cable assembly, wherein said fiber
optic, strand passes into said sealed chamber, and said electronics
assembly is disposed within said sealed chamber.
3. The catheter assembly as recited in claim 2, wherein one of said
first tube and said second tube contains a gas flowing into said
sealed chamber, and the other of said first tube and said second
tube contains said gas flowing out of said sealed chamber.
4. The catheter assembly as recited in claim 2, wherein one of said
first tube and said second tube contains a liquid flowing into said
sealed chamber, and the other of said first tube and said second
tube contains said liquid flowing out of said sealed chamber.
5. The catheter assembly as recited in claim 1, further comprising
a strand disposed within said cable assembly, said strand connected
to a second electronics assembly comprising means for converting
and storing energy conveyed thereto through said strand.
6. The catheter assembly as recited in claim 1, further comprising
a lumen disposed within said cable assembly, said lumen connected
to a second electronics assembly disposed within said distal end of
said cable assembly and comprising a piezoelectric crystal.
7. The catheter assembly as recited in claim 1, further comprising
a second fiber optic strand disposed within said outer tube of said
cable assembly, said second fiber optic strand connected to a
second electronics assembly disposed within said distal end of said
cable assembly.
8. The catheter assembly as recited in claim 7, wherein said second
electronics assembly further comprises a photovoltaic cell.
9. The catheter assembly as recited in claim 7, wherein said second
electronics assembly is a power assembly, and said first
electronics assembly is electrically connected and powered by said
second electronics assembly.
10. The catheter assembly as recited in claim 1, further comprising
a first tube, and a second tube disposed within said outer tube of
said cable assembly and connected to a power assembly disposed
within said distal end of said cable assembly, wherein a portion of
the energy of a fluid flowing from said first tube into said power
assembly and out through said second tube is converted to
electrical energy by said power assembly.
11. The catheter assembly as recited in claim 10, wherein said said
first electronics assembly is electrically connected and powered by
said power assembly.
12. The catheter assembly as recited in claim 1, further comprising
a tube disposed within said outer tube of said cable assembly and
passing into a subassembly disposed within said distal end of said
cable assembly comprising a having an open orifice disposed through
said thin structural wall of said tip assembly.
13. The catheter assembly as recited in claim 12 further comprising
a second fiber optic strand disposed within said outer tube of said
cable assembly and passing into said subassembly, wherein said
subassembly further comprises a second electronics assembly.
14. The catheter assembly as recited in claim 13, wherein said
subassembly further comprises a fluid reservoir.
15. The catheter assembly as recited in claim 14, wherein said
second electronics assembly further comprises means for controlling
the release of fluid from said reservoir through said needle.
16. The catheter assembly as recited in claim 14, wherein said
second electronics assembly further comprises means for controlling
the drawing of fluid from said needle inwardly to said
reservoir.
17. The catheter assembly as recited in claim 16, further
comprising medical analyses means for analyzing fluids drawn in
through said needle.
18. The catheter assembly as recited in claim 1, wherein said cable
assembly further comprises a second fiber optic strand and a third
fiber optic strand disposed within said outer tube of said cable
assembly, said second fiber optic strand and said third fiber
optics strand connected to an optical electronics assembly disposed
within said distal end of said cable assembly; and said tip
assembly further comprises a lens assembly disposed in the outer
surface of said tip assembly, and an optics conduit assembly
connected to said lens assembly and said optical electronics
assembly.
19. The catheter assembly as recited in claim 18, wherein said
optical electronics assembly further comprises a laser diode
providing laser light through said optics conduit assembly
connected to said lens assembly.
20. The catheter assembly as recited in claim 1, wherein said tip
assembly further comprises a receiving coil for receiving radio
frequency electromagnetic waves connected to a power assembly, and
wherein said power assembly is electrically connected to said
electronics assembly.
21. The catheter assembly as recited in claim 1, wherein said tip
assembly further comprises an electromagnetic sensor disposed in
the outer surface thereof and connected to said electronics
assembly.
22. The catheter assembly as recited in claim 1, wherein said tip
assembly further comprises an electromagnetic emitter disposed in
the outer surface thereof and connected to said electronics
assembly.
23. The catheter assembly as recited in claim 1, further comprising
a radio frequency generator disposed within said cavity formed
within said thin structural wall of said tip assembly, wherein said
radio frequency generator is connected to said electronics assembly
and to said coil assembly.
24. The catheter assembly as recited in claim 1, further comprising
a second fiber optic strand disposed within said outer tube of said
cable assembly, said second fiber optic strand extending through
said tip assembly to a lens assembly disposed in the outer surface
of said tip assembly.
25. The catheter assembly as recited in claim 1, further comprising
a lumen disposed within said cable assembly, an inflatable bladder
enclosed within a chamber in said tip assembly, wherein said
inflatable bladder is disposed along an orifice in said thin
structural wall of said tip assembly, and wherein said lumen is
connected by a connection assembly to said inflatable bladder.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims the benefit of the filing date of
U.S. provisional patent application Serial No. 60/357,935 filed
Feb. 19, 2002.
[0002] This invention relates in one embodiment to a catheter
assembly, and more particularly to a catheter assembly that
includes the capability to perform magnetic resonance imaging.
FIELD OF THE INVENTION
[0003] A catheter assembly which is provided with a distally
positioned magnetic resonance imaging coil, thereby enabling high
resolution magnetic resonance imaging of tissue proximate to the
assembly.
BACKGROUND OF THE INVENTION
[0004] Magnetic resonance imaging (MRI) is rapidly becoming an
imaging method of choice for most non-invasive diagnostic
procedures due to a variety of advantages. MRI is particularly
effective in the imaging of internal organs, because images
produced by MRI have superb soft tissue contrast, the imaging
process is not obstructed by bone, and it is straightforward to
obtain multi-plane images without repositioning patient. MRI is
harmless to a majority of patients, as it requires no ionizing
radiation or toxic contrast agents. It provides highly precise and
clear images, thereby enabling functional analysis capabilities and
a rapidly emerging medical practice of MRI-guided surgery.
[0005] However there remains opportunity for further improvement of
MRI. Present MRI capabilities are still unable to image disease
conditions where exceptional tissue morphological or spectral
resolution is required, such as the diagnosis of "vulnerable
plaques" (see Peter Libby, "Atherosclerosis: The New View,"
Scientific American, May 2002, Volume 286, number 5, pages 46-55).
It is well known to those skilled in the art that reducing the
distance between the tissues to be imaged by MRI and the receive
coil in the MRI unit will enhance the signal from the tissues and
thereby improve the quality of the magnetic resonance image,
specifically by improving the tissue magnetic resonance image
signal-to noise ratio.
[0006] The present invention provides such a reduction in the
distance between the tissues to be imaged by MRI. The present
invention provides a small diameter MRI imaging coil that can be
placed within the body, such as natural body openings or punctures
through the skin, and to enable the coil to be positioned close to
the tissues to be imaged, thereby providing significant improvement
in morphological or spectral image quality due to the enhanced
signal from the tissues and the increase in tissue magnetic
resonance image signal-to-noise ratio that this closer proximity
provides. The present invention may be further combined with other
diagnostic and therapeutic features and capabilities useful for the
diagnosis and treatment of diseases. In the preferred embodiment,
the present invention is provided as a catheter device.
[0007] Heretofore, a number of patents and publications have
disclosed catheter devices, the relevant portions of which may be
briefly summarized as follows:
[0008] U.S. Pat. No. 6,236,879, for a "Fiber optic catheter
system," discloses "A catheter system including a catheter having a
proximal end and a distal end and a device for determining the
position of the distal end of the catheter relative to the position
of the proximal end of the catheter, the device for determining the
position including a glass fiber within a lumen of the catheter,
the lumen being defined by a wall, a first polarization filter near
the proximal end of the catheter, and a second polarization filter
near the distal end of the catheter, wherein the first and second
polarization filters are fixed with respect to the wall, and
wherein the glass fiber is suitable for transporting polarized
light while maintaining the direction of the polarization of the
light substantially unchanged during torsional stress of the
catheter."
[0009] U.S. Pat. No. 6,166,806, for a "Fiber optic catheter for
accurate flow measurements," discloses "A two-fiber optic probe or
sensor performs accurate measurements of fluids flowing within a
remote vessels, such as blood flowing within arteries or veins or
fluid flowing within pipes."
[0010] U.S. Pat. No. 5,973,779, for a "Fiber-optic imaging probe,"
discloses "A fiber-optic imaging probe is disclosed for use in
dynamic light scattering applications. The probe includes two
monomode optical fibers and two GRIN lenses to form a pair of
identical fiber-lens combinations."
[0011] U.S. Pat. No. 5,415,653, for a "Optical catheter with
stranded fibers," discloses "A catheter having an axis extending
between a proximal end and an opposing distal end includes a
plurality of optical fibers arranged to spiral in a first direction
to form a circumferential layer around the axis."
[0012] U.S. Pat. No. 4,991,590, for a "Fiber optic intravascular
blood pressure transducer," discloses "A device for the measurement
of the blood pressure of a patient includes an arrangement for
transmitting a light through an optical fiber; an arrangement for
receiving and measuring a reflected light through an optical fiber;
and a cylindrically shaped pressure sensor having a side window and
a plate having two sections which moves in accordance with the
applied blood pressure thereby causing the reflection and detection
of different amounts of light based on the applied blood pressure
at the window."
[0013] U.S. Pat. No. 5,919,135, for a "System and method for
treating cellular disorders in a living being," discloses " . . . .
The invention employs a computerized imaging system (such as CAT
scan, MRI imaging, ultrasound imaging, infrared, X-ray, UV/visible
light fluorescence, Raman spectroscopy, single photon emission
computed tomography or microwave imaging) to sense the position of
a drug infusing catheter within the body . . . . "
[0014] U.S. Pat. No. 6,026,316, for a "Method and apparatus for use
with MR imaging," discloses, "The invention is an apparatus and
method for targeted drug delivery into a living patient using
magnetic resonance (MR) imaging. The apparatus and method are
useful in delivery to all types of living tissue and uses MR
Imaging to track the location of drug delivery and estimating the
rate of drug delivery. An MR-visible drug delivery device
positioned at a target site (e.g., intracranial delivery) delivers
a diagnostic or therapeutic drug solution into the tissue (e.g.,
the brain). The spatial distribution kinetics of the injected or
infused drug agent are monitored quantitatively and non-invasively
using water proton directional diffusion MR imaging to establish
the efficacy of drug delivery at a targeted location."
[0015] U.S. Pat. No. 6,052,613, "Blood pressure transducer,"
discloses, "This invention relates to a blood pressure transducer
(8) and provides a safe and economical transducer by providing a
novel optical fiber (80) made of a transparent elastomer. The
present invention provides an invasive direct blood pressure
transducer (8) of an external sensor system consisting of a
catheter (1a), a pressure tub (6) connected to the catheter at one
of the ends thereof and a pressure transducer (8) connected to the
other end of the pressure tube (6), part of the pressure transducer
is composed of an optical fiber (80) made of a transparent
elastomer."
[0016] U.S. Pat. No. 5,445,151, for a "Method for blood flow
acceleration and velocity measurement using MR catheters,"
discloses "A method of magnetic resonance (MR) fluid flow
measurement within a subject employs an invasive device with an RF
transmit/receive coil and an RF transmit coil spaced a known
distance apart. The subject is positioned in a static magnetic
field. The invasive device is positioned in a vessel of a subject
in which fluid flow is desired to be determined. A regular pattern
of RF transmission pulses are radiated through the RF
transmit/receive coil causing it to cause a steady-state MR
response signal. Intermittently a second RF signal is transmitted
from the RF coil positioned upstream, which causes a change in the
steady-state MR response signal sensed by the downstream
transmit/receive coil. This is detected a short delay time later at
the RF receive coil. The time delay and the distance between the RF
coils lead directly to a fluid velocity. By exchanging the position
of the RF transmit and transmit/receive coils, retrograde velocity
may be measured. In another embodiment, more RF coils are employed.
The changed MR response signal may be sensed at a number of
locations at different times, leading to a measured change in
velocity, or acceleration of the fluid."
[0017] U.S. Pat. No. 6,134,003, for a "Method and apparatus for
performing optical measurements using a fiber optic imaging
guidewire, catheter or endoscope," discloses, "An imaging system
for performing optical coherence tomography includes an optical
radiation source; a reference optical reflector; a first optical
path leading to the reference optical reflector; and a second
optical path coupled to an endoscopic unit."
[0018] U.S. Pat. No. 5,830,209, for a "Multi-fiber laser catheter,"
discloses "Laser catheters according to the invention include
multiple optical fibers for delivery of laser energy to a
pre-determined treatment site in the therapeutic treatment of
cardiac tissue. A fixation device fixes the distal end of the
catheter to the treatment site. Temperature sensing devices
disposed on the fixation device provide a temperature depth profile
of the tissue treatment site, which can be used to control the
treatment. Multi-piece, single-piece and porous tip catheters are
disclosed."
[0019] U.S. Pat. No. 6,024,738, for a "Laser catheter apparatus for
use in arteries or other narrow paths within living organisms,"
discloses "A laser catheter for the treatment of lesions and plaque
deposits in arteries and other narrow paths having a radiation
assembly affixed to a flexible conduit. The conduit generally
includes multiple lumens for the passage of an optical fiber, a
guide wire, a cooling medium therethrough, or fluid for inflating
an angioplasty balloon."
[0020] U.S. Pat. No. 5,634,720, for a "Multi-purpose
multi-parameter cardiac catheter," discloses "A multi-lumen,
multi-purpose cardiac catheter which incorporates optical filaments
and an optical coupler for use with external apparatus for
determining the oxygen concentration in the blood of a patient
under critical care conditions, as well as incorporating therein a
thermal element useable with a second external apparatus for
measurement of continuous cardiac output."
[0021] U.S. Pat. No. 5,435,308, for a "Multi-purpose
multi-parameter cardiac catheter," discloses "A multi-lumen,
multi-purpose cardiac catheter which incorporates optical filaments
and an optical coupler for use with external apparatus for
determining the oxygen concentration in the blood of a patient
under critical care conditions, as well as incorporating therein a
heater coil useable with a second external apparatus for
measurement of continuous cardiac output. The catheter also
includes a thermistor and at least one injectate port for enabling
the user to also conduct thermal dilution readings and obtain
intermittent measurements of cardiac output. The combination of a
thermal dilution catheter with a SVO2 catheter and a continuous
cardiac output catheter gives the multi-purpose catheter above
described substantial versatility as well as providing the user
with a versatile cardiac catheter device which enables him to
conduct multiple evaluations of disparate blood-related parameters
which require the use of separate apparatus. Simply by switching
from one external apparatus to the other, the user can obtain
readings for different blood-related parameters useful in the
treatment of the cardiac patient."
[0022] U.S. Pat. No. 6,036,654, for a "Multi-lumen, multi-parameter
catheter," discloses "A multi-lumen catheter capable of measuring
cardiac output continuously, mixed venous oxygen saturation as well
as other hemodynamic parameters. The catheter is also capable of
undertaking therapeutic operations such as drug infusion and
cardiac pacing. The catheter includes optical fibers for coupling
to an external oximeter, an injectate port and thermistor for bolus
thermodilution measurements, a heating element for inputting a heat
signal and for coupling to an external processor for continuously
measuring cardiac output, and a distal lumen for measuring
pressure, withdrawing blood, guidewire passage or drug infusion. In
a preferred embodiment, the catheter includes a novel lumen
configuration permitting an additional infusion lumen for either
fast drug infusion or cardiac pacing."
[0023] The disclosures of U.S. Pat. Nos. 6,236,879, 6,166,806,
5,973,779, 5,415,653, 4,991,590, 5,919,135, 6,026,316,6,052,613,
5,445,151, 6,134,003, 5,830,209, 6,024,738, 5,634,720, 5,435,308,
and 6,036,654 are incorporated into this disclosure by
reference.
[0024] Despite the advances in capabilities that are described in
these numerous catheter devices, there remain shortcomings in the
capabilities of these catheter devices, and in magnetic resonance
imaging, and in the use of magnetic resonance imaging when these
catheter devices are present in the body. As was previously
described, there is a need to reduce the distance between the
tissue to be imaged by MRI and the receive coil in the MRI unit.
Because of the relatively large distance between the external
receive coil in present MRI systems and the internal tissue of the
patient, the signal-to-noise ratio is insufficient to provide a
satisfactory image of certain tissues in many circumstances.
[0025] Many of these catheter devices are dangerous to the patient,
because when such catheter devices are exposed to the MRI
procedure, the metallic wires, tubing, structural supports, and
other metallic leads therein are heated by the effect of the high
frequency magnetic field. In addition, the functionality of these
catheter devices is generally limited to a single purpose. It would
be particularly beneficial to have a catheter device provided with
multiple diagnostic features or capabilities in a single lead,
and/or provided with diagnostic and therapeutic features in a
single lead. In particular, it is highly desirable to incorporate
an MRI coil into a catheter having additional diagnostic features
or capabilities.
[0026] It is therefore an object of this invention to provide a
small diameter MRI imaging coil that can be placed within the body,
such as natural body openings or punctures through the skin, and to
enable the coil to be positioned close to the tissues to be imaged,
thereby providing significant improvement in morphological or
spectral image quality due to the enhanced signal from the tissues
and the increase in tissue magnetic resonance image signal-to-noise
ratio that this closer proximity provides.
[0027] It is a further object of the present invention to combine
with the present invention other diagnostic and therapeutic
features and capabilities useful for the diagnosis and treatment of
diseases.
SUMMARY OF THE INVENTION
[0028] In accordance with the present invention, there is provided
a catheter assembly comprising a cable assembly having a proximal
end and a distal end, said cable assembly further comprising an
outer tube, a first electronics assembly disposed within said
distal end of said cable assembly, and a first fiber optic strand
disposed within said tube and connected to said first electronic
assembly; and a tip assembly connected to said distal end of said
cable assembly further comprising a thin structural wall and a
cavity formed within said thin structural wall, and a coil assembly
disposed within said cavity, wherein said coil assembly is
connected to said first electronics assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The invention will be described by reference to the
following drawings, in which like numerals refer to like elements,
and in which:
[0030] FIG. 1 is a schematic of a cross section of a catheter
bundle of optical strands,
[0031] FIG. 2 is a schematic of a cross section of a catheter
bundle of optical and support strands,
[0032] FIG. 3 is a schematic of a cross section of a catheter
bundle of optical, strands, tubes, and support strands, and
[0033] FIGS. 4-14 each schematically illustrate a numerous
embodiments of a catheter cable and tip.
[0034] The present invention will be described in connection with a
preferred embodiment, however, it will be understood that there is
no intent to limit the invention to the embodiment described. On
the contrary, the intent is to cover all alternatives,
modifications, and equivalents as may be included within the spirit
and scope of the invention as defined by the appended claims.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] For a general understanding of the present invention,
reference is made to the drawings. In the drawings, like reference
numerals have been used throughout to designate identical elements.
In describing the present invention, the terms distal and proximal
ends are used to describe the catheter embodiments disclosed
herein. As used herein, the proximal end of a catheter is meant to
describe the end thereof that is external to the body in which it
is disposed. The distal end of a catheter is meant to describe the
end thereof that is internal to the body in which it is disposed.
The catheter terminates within such a body at the distal end of
such catheter. FIGS. 4-14 of this disclosure depict distal ends of
catheters of the present invention.
[0036] FIG. 1 is a cross-sectional view of a catheter cable
assembly 100. Such catheter cable assembly 100 is typical of prior
art optical cable assemblies. Reference may be had, e.g., to U.S.
Pat. No. 4,784,461 (optical cable with improved strength), U.S.
Pat. No. 6,259,843 (optical cable), U.S. Pat. No. 5,611,016
(dispersion balanced optical cable), U.S. Pat. No. 4,911,525
(optical communications cable), U.S. Pat. No. 4,798,443 (optical
cable), U.S. Pat. No. 5,634,720 (multi-purpose multi-parameter
cardiac catheter), and the like. The entire disclosure of each of
these United States patents is hereby incorporated by reference
into this specification.
[0037] Referring to FIG. 1, and in the preferred embodiment
depicted therein, six fiber optic strands 102 are shown surrounding
a central fiber optic strand 103. It is to be understood that the
number of strands 102 in the assembly 100 of the catheter cable may
be more or less than the number depicted. In one embodiment, from
about 1 to about 10 such fiber optic strands 102 may be used.
[0038] Referring again to FIG. 1, it is preferred that each such
fiber optics strand 102/103 be comprised of a core 108. This core
108 preferably consists of or consists essentially of silicon
dioxide (silica), preferably of high purity. The core 108 generally
has a symmetrical cross section, such as a circular cross section;
and it usually has a diameter of from about. 1 to about 100
microns. In one embodiment, core 108 has a diameter of from about 2
to about 10 microns.
[0039] Cladding 106 preferably envelops the core 108. In the
embodiment depicted, the cladding 106 has an outside diameter that
is substantially larger than core 108, being at least about 1.1
times as large as the diameter of the core. In general, the
cladding generally has a diameter of from about 5 to about 150
microns. In one embodiment, the optical cladding 106 has a
thickness of approximately 60 micrometers and is itself preferably
surrounded by a protective film 104. The protective film 104
preferably consists essentially of plastic material and, in one
embodiment, has a thickness of approximately 1 micrometer. In the
embodiment depicted in FIG. 1, six (6) of these fiber optic strands
102 comprising core 108 and cladding 106 are positioned around a
central fiber optic strand 103.
[0040] In the embodiment depicted, the seven fiber optic strands
102/103 of FIG. 1 are surrounded by a protective layer comprising a
sleeve or tube 110, which keeps the seven individual, strands
102/103 together. Such outer tubing 110 may be made from flexible
material such as, e.g., plastic.
[0041] The regions 114 disposed between fiber optic strands 102/103
in one embodiment are preferably filled with additional material
114 to provide for increased structural strength of the overall
assembly 100. In one embodiment, the additional material 114 is
plastic material. In another embodiment, the additional material
114 is steel fiber or carbon fiber. In one embodiment, it is
preferred that none of the materials within the cable assembly 100,
and/or the cable assembly 120 (see FIG. 2) be electrically
conductive.
[0042] In one embodiment, illustrated in FIG. 1, some or all of the
outer regions 112 are filled with the same additional material(s)
within spaces 114, and/or different additional material.
Furthermore, some of these spaces 114/112 may be filled with
additional material, whereas others are not.
[0043] Fewer or more interstrand regions 114/112 will exist
depending on the total number of strands comprising the catheter
cable assembly 100. The choice of material depends, in part, on the
desired flexibility and strength of the catheter cable assembly
100.
[0044] FIG. 2 is a sectional view of an optical cable assembly 120
in which a central strand 122 is preferably comprised of, or
consists essentially of, a single, solid material. In this
embodiment, strand 122 may be used to give the catheter cable
additional structural strength or flexibility. The additional,
solid material 122 may be a plastic material, may be optically
inert, and may preferably be electrically insulative.
[0045] It is preferred that the material 122 have low magnetic
susceptibility. Thus, e.g., the material 122 can be made of
glass-epoxy, quartz glass, or other material having a low magnetic
susceptibility. As is known to those skilled in the art, magnetic
susceptibility is measured by the ratio of the intensity of
magnetization produced in a substance to the magnetizing force or
intensity of field to which it is subjected.
[0046] FIG. 3 depicts another embodiment of another cable strand
assembly 130 in which two of the fiber optics strands 102 of FIG. 2
are replaced by lumens 132 and 134.
[0047] As will be apparent, these lumens may comprise and/or convey
cooling fluid(s) or gas(es), heat exchange fluids or gases, and the
like. The lumens 132 and/or 134 may be pressured. The lumens 132
and/or 134 may be partially evacuated.
[0048] In the preferred embodiment depicted in FIG. 3, lumens 132
and/or 134 preferably comprise a wall 136 of approximately 1 to 2
micrometers thick and an axial void 138 of approximately 125
micrometers in diameter.
[0049] FIG. 4 is a schematic representation of an assembly 200
comprised of a cable assembly 204 and a catheter tip assembly 201
connected to the cable assembly 204 at the distal end of the
catheter (not shown).
[0050] As is known to those skilled in the art, a catheter is a
tubular instrument adapted to allow passage of fluid, other
material, or energy from or into a body cavity or blood vessel. As
used herein, the term "catheter" refers to a tubular cable assembly
connected to a tip comprised of a thin structural wall and a cavity
enclosed therein, containing means for converting photonic energy
to electrical energy, and vice versa.
[0051] Referring again to FIG. 4, catheter tip assembly 201
comprises a thin structural wall 202 containing a volume or cavity
218, within which a variety of small devices may be disposed.
Catheter cable 204 preferably comprises at least two tubes 206 and
208 and a fiber optics strand 210. These tubes/strand 206/208/210
preferably pass into a sealed chamber 212. Disposed within the
volume 214 of the chamber 212 is an electronic transducer assembly
216 connected to the fiber optics strand 210 and also connected to
a coil assembly 220 situated outside the chamber 212, but within
the tip volume 218. The connection of the electronic assembly 216
to the coil assembly 220 is preferably made by conductors 222 and
224.
[0052] The coil assembly 220 is preferably one or more pick-up
coils and/or one or more transmit coils suitable for magnetic
resonance imaging procedures. As is known to those skilled in the
art, pickup coils are adapted to sense a signal or quantity.
Reference may be had, e.g., to U.S. Pat. No. 4,691,164, which also
describes coil 120 as being a "transmitter/receiver." Reference
also may be had, e.g. to U.S. Pat. Nos. 4,450,408, 6,278,277,
5,061,680, 5,158,932, and the like. The entire disclosure of each
of these United States patents is hereby incorporated by reference
into this specification.
[0053] Referring again to FIG. 4, the lumens 206 and 208 may be
used, e.g. to cycle air through the chamber 212 to provide a
cooling means for the electronics assembly 216. Such a flow may be
made into and out of chamber 212, as is indicated by the flow
direction arrows 226 and 228. Alternatively, a liquid may be cycled
through the chamber 212 for the purposes of assisting and
controlling the dissipation of heat generated by the electronics
assembly 216.
[0054] In another embodiment (not shown), the catheter cable
assembly 204 of FIG. 4 additionally contains a strand suitable for
steering the catheter tip through the lumens of the body.
[0055] In another embodiment, illustrated in FIG. 5, one preferred
assembly 250 of the distal end of the catheter cable assembly 252
and catheter tip 254 is illustrated. The cable assembly 252
consists of at least two strands 256 and 258. As will be apparent,
the assembly 250 includes two separate electronic assemblies 260
and 262, and two strands 256 and 258.
[0056] Referring to FIG. 5, and in the preferred embodiment
depicted therein, strand 256 is preferably connected to an
electronic assembly 260 that preferably houses means for converting
and storing energy conveyed to it through strand 256.
[0057] In one embodiment, depicted in FIG. 5, strand 256 is hollow
tube or lumen filled with a gas (such as air), and/or a liquid,
and/or a solid material(s). In this embodiment, the power assembly
260 may contain a piezoelectric crystal (not shown), one or more
capacitors (not shown), one or more inductors (not shown), one or
more resistors (not shown), and other electronic components,
circuits, and assemblies (not shown).
[0058] Referring again to FIG. 5, and in one embodiment, the end of
lumen 256 is connected to the piezoelectric crystal (not shown) in
such a way as to oscillate the piezoelectric crystal as the
pressure in the tube 256 is oscillated by an external means (not
shown). By such a device, one can convert a pressure signal into an
electrical signal, and vice versa. If one were to add photoelectric
devices to this assembly, one would also be able to convert
pressure signals to photonic signals, and vice versa.
[0059] As will be apparent, in the embodiment depicted in FIG. 5,
hydraulic energy/signals may be converted to electrical
energy/signals, and vice versa, by piezoelectric transducer
assembly 260. Thus, in addition to conveying information
photonically, the device 250 is also capable of transmitting
information hydraulically.
[0060] In another embodiment, strand 256 is a fiber optics cable.
Power assembly 260 may contain a photovoltaic cell (not shown)
along with a capacitor (not shown). An external laser diode (not
shown) may preferably send light through the strand 256 to the
assembly 260 where it is converted to an electrical potential by a
photovoltaic cell (not shown) which charges the capacitor.
[0061] In the embodiment illustrated in FIG. 5, strand 258 is
preferably a fiber optics strand to be used for sending signals to
the proximal end of the catheter cable 252. Strand 258 is
preferably connected to an electronics assembly 262 at the distal
end of the cable assembly 252. The electronics assembly 262 is
preferably powered by the power assembly 260 through connection
264. The electronics assembly 262 preferably has means (not shown)
for converting and sending signals received by one or more coils
268 through optics strand 258. The coils 268 are connected to the
electronics assembly 262 via lines 270 and 272. In another
embodiment, not shown, the coils 268 are telemetrically connected
to the electronics assembly 262.
[0062] In one embodiment, not shown, several coils 268 are
positioned at various angles to enhance the imaging ability of the
catheter. As will be apparent, the angles at which radiation
impacts an antenna often affect its receiving capabilities.
[0063] In another embodiment, not shown, the coil 268 may be
rotated and/or translated into various angles and locations within
the tip assembly by an actuator (not shown) controlled by
electronics assembly 262.
[0064] FIG. 6 illustrates another embodiment of this invention
comprising an assembly 300 comprised of a catheter cable assembly
302 and a distal end tip 304. The cable assembly 302 contains at
least tubes 306 and 308 connected to a power assembly 312, and at
least one fiber optics strand 310 connected to an electronics
assembly 314. In this embodiment, liquid (or gas) may be cycled
through the power assembly 312 which is so constructed, in one
embodiment, as to convert the motion of the fluid through assembly
312 or to convert the contents of the liquid (or gas) into
electrical energy suitable for running the electronics in assembly
314. The liquid or gas, e.g. may contain electrolytes, and assembly
312 may be so constructed as to comprise a battery. The power
assembly 312 is connected to the electronics assembly 314 via line
316.
[0065] In one embodiment, the electronics assembly 314 is connected
to the fiber optics strand 310 and is used to convey signals
obtained from coils 320, which are connected to the electronics
assembly 314 via lines 322 and 324, through the optics strand 310.
Additionally, strand 310 may be used to send signals from the
external proximal end (not shown) of the cable assembly 302 to the
electronics assembly 314.
[0066] In another embodiment depicted in FIG. 7, an assembly 350 is
shown comprising a catheter cable assembly 352 and a catheter tip
assembly 354. The catheter cable assembly comprises at least 3
strands, 356, 358, 360.
[0067] In this embodiment, strands 356 and 358 are connected to a
subassembly 370. Subassembly 370 is connected to a syringe needle
372 that has an open orifice 374 in the tip 354. In one embodiment
of the configuration depicted in FIG. 7, strand 356 is a hollow
tube and strand 358 is a fiber optic. Subassembly 370 may consist
of a reservoir (not shown) and electronic means (not shown) for
controlling the release of the reservoir contents through the
needle 372. Strand 356 is then used to fill the reservoir with the
desired solution, e.g. an MRI contrast agent or drug, or topical
ointments, etc. Strand 358 may be used to communicate externally
with the electronics of subassembly 370 to signal when the solution
stored in the reservoir is to be released.
[0068] In another embodiment of FIG. 7, not shown, the needle 372
is used to obtain fluid samples from the body. In this embodiment,
tube strand 356 is used to provide a vacuum pressure suitable for
drawing the bodily fluid through the needle 372. Subassembly 370 is
so constructed as to provide means for controlling the drawing of a
fluid through the needle 372. Subassembly 370 may also contain
medical analyses means (not shown) suitable, e.g. for detecting
glucose levels in blood, for detecting toxins in the blood, for
determining the pH level of the sampled fluid, etc. Subassembly 370
also preferably has means (not shown) for sending data pertaining
to the results of such analysis through the fiber optics strand 358
to an external monitor or physician (not shown). Additionally,
strand 358 may be used to send command signals from an outside
physician to the subassembly 370 to control the drawing of fluid
and to direct the analysis of said drawn fluid.
[0069] Referring again to FIG. 7, the electronics assembly 362 is
preferably connected to the fiber optics strand 360 and is used to
convey signals obtained from one or more coils 364, which are
connected to the electronics assembly 362 via lines 366 and 368,
through the optics strand 360. Additionally, fiber optics stand 360
may be used to send signals from the external proximal end (not
shown) to the cable assembly 352 to the electronics assembly
362.
[0070] FIG. 8 depicts another embodiment of an assembly 400
comprised of a catheter cable assembly 402 and a tip assembly 404.
The catheter cable assembly 402 comprises of at least 3 strands
406, 408, 410 that, in this embodiment, are all preferably fiber
optics strands. In this embodiment, strands 406 and 408 are
connected to optical electronics assembly 420. Also connected to
optical electronics assembly 420 is an optics conduit assembly 422
that is connected to a lens assembly 424 built into the outer
surface of the tip assembly 404. The optical electronics assembly
420, optics conduit assembly 422 and lens assembly 424 may comprise
the components of an optical biopsy assembly or may provide means
for performing Optical Coherent Tomography. In these cases, the
optics strand 406 may convey the light to be used for the optical
biopsy procedures, while optics strand 408 is used by the
electronics assembly 420 to convey the biopsy information back to
the physician or external monitoring device (not shown).
Additionally, optical electronics assembly 420, optics conduit
assembly 422, and lens assembly 424 may be used for laser ablation
at the tip site. Laser light may be generated by a laser diode
built into optical electronics assembly 420, or may be obtained
from an external source through strand 406. In another embodiment,
the functionality of strand 406, optical electronics assembly 420,
optics conduit assembly 422 and lens assembly 424 is switched
between performing, e.g., optical coherent tomography and laser
ablation. Such functional switching may be controlled externally by
communication between an external physician and the optical
electronics assembly 420 Via fiber optic strand 408.
[0071] In another embodiment, and continuing to refer to FIG. 8,
the electronics assembly 420 and optics assemblies 422 and 424 are
utilized to provide video images of the external tip environment
(not shown) through the optical strand 406 to the proximal end of
the catheter.
[0072] Continuing to refer to FIG. 8, the electronics assembly 412
is preferably connected to the fiber optics strand 410 and is used
to convey signals obtained from coils 414, which are connected to
the electronics assembly 412 via lines 416 and 418, through the
optics strand 410.
[0073] FIG. 9 depicts another embodiment of an assembly 500
comprising a cable assembly 502 and a tip assembly 504. In this
embodiment, at least one fiber optic strand 508 is disposed within
the catheter cable assembly 502. It is connected, within a tip
cavity region 506, to an electronics assembly 510. The electronics
assembly is connected to at least one coil 512 by means of lines
514 and 516. Signals from the coils 512 are converted into light
signals by the electronics assembly 510 and sent out through the
fiber optic strand 508. The power to run the electronics assembly
510 is preferably provided by a power electronics assembly 520,
which is connected to at least one coil 518 via lines 522 and 524.
In magnetic resonance imaging (MRI) technology, external radio
frequency electromagnetic waves are applied to the a body in order
to excite protons in the nuclei of the body's atoms. The coils 518
and power electronics 520 are so designed as to resonate at the
externally applied radio frequency wave frequency. In this way,
energy may be delivered, and possibly stored in capacitors (not
shown) within power electronics assembly 520. The electrical power
is provided to the electronics assembly 510 via line 526.
[0074] FIG. 10 depicts another embodiment of an assembly 550
comprising a cable assembly 552 and a tip assembly 554. In this
embodiment, the cable assembly 552 comprises of at least one optics
strand 556 connected to an electronics assembly 558. The
electronics assembly 558 is connected to at least one pickup coil
560 via lines 562, 564. The electronics assembly 558 converts the
signals picked up by the coils into light signals suitable for
transmission through the fiber optics strand 556 and generates and
transmits such signals. Additionally, other sensors 566, and
electromagnetic emitters 570 are connected to the electronics
assembly 558 via lines 568 and 572. Sensors 566 and emitters 570
are also connected to, and may protrude through, the tip 554.
Sensors 566 may be used, e.g., to sense the temperature, blood
pressure, blood flow rate, etc. within a body. Emitters 570 may be
used, e.g. to emit millimeter electromagnetic energy, or heat, or
other energy. The electronic assembly 558 collects sensed data from
the sensors and converts the data into light signals suitable for
transmission through the fiber optics strand 556. Electronics
assembly 558 also controls and coordinates which datum from which
sensor and/or coil is to be transmitted through fiber optics strand
556 at ay given time.
[0075] FIG. 11 depicts another embodiment of an assembly 600
comprising a cable assembly 602 and a tip assembly 604. The cable
assembly 602 comprises at least 2 fiber optic strands 606, 608
connected to an electronics assembly 610. The electronics assembly
610 is connected to at least one sensing device, including, but not
limited to, a pickup coil 612. Other, optional, sensing devices are
labeled as 618. The electronics assembly 604 is connected to the
pickup coil 612 via lines 614, 616. The other sensing devices are
connected to the electronics assembly 610 via line 620.
[0076] In this embodiment, laser light, or other suitable light, is
sent from an external source (not shown) through fiber optics
strand 606 as indicated by arrow 622 to the electronics assembly
610. The electronics assembly modifies the light in a predetermined
way to encode the signals from the coil 612 and/or the sensing
devices 618 and then channels the light through the fiber optics
strand 608, as indicated by arrow 624. In this way, a source for
generating light is not required at the electronics assembly 610.
One method for encoding a signal is to construct electronics
assembly 610 with optical components suitable for causing phase
shifts in the light 622 based on signals from the coil 612 or other
sensing devices 618. Then, by externally comparing the phase
between the light sent in 622 with that of the light sent out 624,
a means for transmitting sensed data is realized. Other means for
altering the incoming light 622 before channeling it out as 624 may
be utilized. Using such techniques reduces the power requirements
of the electronics assembly 610 since, in these embodiments,
electronics assembly 610 does not need a light source. Also, this
provides a way to utilize light sources that might not otherwise be
applicable if it were required to be part of the electronics
assembly 610 because of size constraints, power requirements, or
heating problems. Using an external light source as described here
eliminates these constraints.
[0077] In another embodiment depicted in FIG. 12, a distal end
catheter assembly 650 comprises a catheter cable assembly 652 and a
tip assembly 654 suitable for performing radio frequency ablation
within a body. Other frequencies of electromagnetic energy outside
of the radio frequency range may also be utilized. The catheter
cable assembly comprises at least one optical strand 656 connected
to an electronic assembly 658 which contains means for converting
the optical energy sent from the external proximal end of the
catheter (not shown) to the electronic assembly 658 at the distal
end of the catheter. Such means for converting the optical energy
to electrical energy may be, e.g., a photovoltaic cell. Electronic
assembly 658 may also be comprised of other electronic components
as well. The electronic assembly 658 is connected to an radio
frequency signal generator 660 via line 668. The radio frequency
signal generator 660 is connected to one or more coils 662 suitable
for performing, e.g. radio frequency ablation, via lines 664,
666.
[0078] In another embodiment (not shown) the radio frequency
generator of the embodiment shown in FIG. 12 is removed. In this
case, the optical energy sent to the electronic assembly 658 of
FIG. 12 is pulsed at the desired radio frequency. Other frequencies
outside of the radio frequency range may also be utilized. The
electronics assembly 658 of FIG. 12 is correspondingly modified to
connect directly to the coils 662 of FIG. 12. In this way, the
amount of electronics, power requirements, heat generation and
possibly other constraints in the design of the catheter tip may be
reduced.
[0079] FIG. 13 depicts another embodiment of an assembly 700
comprised of a catheter cable assembly 702 and a tip assembly 704.
The catheter cable assembly 702 comprises 2 strands 706, 708 that,
in this embodiment, are all preferably fiber optic strands. In this
embodiment, strand 706 passes through the tip area 712 and connects
to a lens assembly 710. Thus, electromagnetic energy (such as,
e.g., optical energy, microwave energy, millimeter wave energy, and
the like) from a source (not shown) at the remote proximal end of
the catheter cable 702 may be directly applied to the tip 704 and
to the external environment disposed beyond it.
[0080] In one embodiment, the electromagnetic energy conveyed
through 706 is outside of the visible electromagnetic spectrum,
includes the near infrared, and/or infrared and/or ultraviolet,
and/or other ranges of the electromagnetic spectrum. In another
embodiment, and continuing to refer to FIG. 13, the optical energy
passed through the strand 706 and out through the lens assembly 710
is a laser light adapted to apply heat to the environment proximate
to the tip. In another embodiment, the laser energy may be utilized
for cauterization.
[0081] Continuing to refer to FIG. 13, the electronics assembly 714
is preferably connected to the fiber optics strand 708 and is
preferably used to convey through optics strand 708 the signals
obtained from coils 716 that are connected to the electronics
assembly 714 via lines 718 and 720.
[0082] FIG. 14 depicts another embodiment of the invention,
illustrating an assembly 750 comprised of a catheter cable assembly
752 and a tip assembly 754: The catheter cable assembly 752
comprises two strands 758, 760. Strand 758 is preferably a hollow
lumen or tube suitable for transporting a gas or a liquid. Strand
760 is preferably a fiber optic strand. In this embodiment, strand
758 connects to one or more inflatable bladders 764 disposed within
the tip volume 756. The connection of the tube 758 to the
bladder(s) is accomplished via connection assembly 766. The bladder
is further enclosed within a chamber 776 within the tip volume 756
which provides the necessary constraints on the bladder 764 such
that when a gas or liquid is pumped into the bladder 764, said
bladder 764 can not extend into the tip volume 756. The bladder 764
is so disposed as to be able to expand out of the tip 754 through
orifice 762 of tip 754. In this way, the catheter tip 754 may be
stabilized within the body environment (not shown) to which said
tip is introduced. Applying a partial vacuum to the tube 758
retracts the bladder 764.
[0083] Continuing to refer to FIG. 14, the electronics assembly 768
is preferably connected to the fiber optics strand 760 and is used
to convey signals obtained from one or more coils 770, which are
connected to the electronics assembly 768 via lines 772 and 774,
through the optics strand 760. The electronic assembly 768 may
contain means for decoupling the coils 770 with respect to the
externally applied (not shown) magnetic resonance imaging radio
frequency and/or gradient magnetic field oscillations.
Additionally, electronics assembly 768 may contain means for
converting the signals picked up by the coils 770 into digital
signals or analog signals suitable for transmission through the
fiber optics strand 760. Multiplexing of signals may also be used
to transmit and/or receive signals through fiber optics strand
760.
[0084] In another embodiment (not shown), one or more bladders are
disposed along the cable assembly 752 of FIG. 14, rather than or in
addition to the bladders in the tip 754 of FIG. 14.
[0085] In another embodiment (not shown), extendable and
retractable wires are used to increase the stability of the
catheter tip.
[0086] It is, therefore, apparent that there has been provided, in
accordance with the present invention, a catheter assembly that is
compatible with and that may be subjected to a magnetic resonance
imaging process without adverse effects on the assembly, or the
patient within whom it is disposed. While this invention has been
described in conjunction with preferred embodiments thereof, it is
evident that many alternatives, modifications, and variations will
be apparent to those skilled in the art, and that changes can be
made in the apparatus, in the ingredients and their proportions,
and in the sequence of combinations and process steps, as well as
in other aspects of the invention discussed herein. Accordingly, it
is intended to embrace all such alternatives, modifications and
variations that fall within the spirit and broad scope of the
appended claims.
* * * * *